Modelling of Flange Joints for the Nonlinear Dynamic Analysis of Gas Turbine Engine Casings

2012 ◽  
Author(s):  
C. W. Schwingshackl ◽  
E. P. Petrov
Keyword(s):  
Nonlinear Analysis ◽  
Gas Turbine ◽  
Nonlinear Dynamic Analysis ◽  
Aircraft Engine ◽  
Partial Slip ◽  
Analysis Tool ◽  
Nonlinear Behaviour ◽  
Flange Joint ◽  
Contact Interface ◽  
Contact Behaviour

The finite element analysis of individual components of aircraft engine casings provides high accuracy and a good agreement with the measured response data. However, when these components are assembled, the accuracy of such predictions can significantly deteriorate since models describing stiffness and friction properties of joints are linearised. A full nonlinear analysis of the casing flanges is required to fully include the influence of the bolted joints, model the flexibility in the contact interface, and consider the nonlinear behaviour of the contact due to partial slip and separation. In this paper different nonlinear models of casings are investigated with an available nonlinear analysis tool; A parametric study of the contact interface meshes is conducted to identify a satisfying analysis approach. The dynamic flange behaviour is analysed in detail, including effects of the bolt and normal load distribution. A comparison of the introduced nonlinear modelling with more traditional rigid or linear-elastic flange joint models is carried out to evaluate the effect of the nonlinear approach. The study demonstrates the nonlinear nature of a casing flange joint and highlights the need to include them in the analysis. The detailed modelling of the contact interaction of joints, gives an insight in the nonlinear contact behaviour of flanges of aircraft engine casings, and the predictive capabilities for the nonlinear analysis of gas turbine engines.

Modeling of Flange Joints for the Nonlinear Dynamic Analysis of Gas Turbine Engine Casings

2012 ◽  
Vol 134 (12) ◽  
Author(s):  
C. W. Schwingshackl ◽  
E. P. Petrov
Keyword(s):  
Nonlinear Analysis ◽  
Gas Turbine ◽  
Normal Load ◽  
Nonlinear Dynamic Analysis ◽  
Aircraft Engine ◽  
Partial Slip ◽  
Analysis Tool ◽  
Flange Joint ◽  
Contact Interface ◽  
Element Analysis

The finite element analysis of individual components of aircraft engine casings provides high accuracy and a good agreement with the measured response data. However, when these components are assembled, the accuracy of such predictions can significantly deteriorate since models describing stiffness and friction properties of joints are linearized. A full nonlinear analysis of the casing flanges is required to fully include the influence of the bolted joints, model the flexibility in the contact interface, and consider the nonlinear behavior of the contact due to partial slip and separation. In this paper different nonlinear models of casings are investigated with an available nonlinear analysis tool: A parametric study of the contact interface meshes is conducted to identify a satisfying analysis approach. The dynamic flange behavior is analyzed in detail, including effects of the bolt and normal load distribution. A comparison of the introduced nonlinear modeling with more traditional rigid or linear-elastic flange joint models is carried out to evaluate the effect of the nonlinear approach. The study demonstrates the nonlinear nature of a casing flange joint and highlights the need to include them in the analysis. The detailed modeling of the contact interaction of joints gives an insight in the nonlinear contact behavior of flanges of aircraft engine casings, and the predictive capabilities for the nonlinear analysis of gas turbine engines.

Characterization of gas turbine ingested sand particles based on electrostatic signal

2021 ◽  
pp. 095765092110464
Author(s):  
Jianzhong Sun ◽  
Heng Jiang ◽  
Caiqiong Yang ◽  
Ruochen Liu
Keyword(s):  
Theoretical Analysis ◽  
Gas Turbine ◽  
Simulation Study ◽  
Aircraft Engine ◽  
In Situ Monitoring ◽  
Service Reliability ◽  
Fem Modeling ◽  
Initial Development ◽  
Sand Particles ◽  
Particle Ingestion

Particle ingestion into a gas turbine can have serious effects on both performance and engine in-service reliability. Thus there exists a need for in situ monitoring and characterizing particulate matter entering an aircraft engine inlet for the purposes of engine damages estimation and prognosis. This paper presents the initial development of Ingested Debris Monitoring System (IDMS) signal processing method of characterizing the ingested particles. A theoretical analysis and simulation study were carried out to study the relationships between the characteristics of the ingested sand particles and the features of the IDMS signal both in frequency- and time-domain. A Finite-Element Modeling (FEM) for the IDMS Sensor was developed, then the validated FEM modeling was used for simulation experiments of particles ingestion under various conditions of different particle moving speeds, concentrations and charge-to-mass ratios. Results of the theoretical analysis and simulation study demonstrates the feasibility and effectiveness of the proposed method to provide real time information characterizing the size and concentration of ingested sand particles, and will serve as an impetus to carry out further research.

Computational Aid to AEDsys for Designing a Variable-Area Gas Turbine Nozzle

2018 ◽  
Author(s):  
Devin O. O’Dowd ◽  
Aaron R. Byerley
Keyword(s):  
Gas Turbine ◽  
United States Air Force ◽  
System Analysis ◽  
Graphical Representation ◽  
Aircraft Engine ◽  
The United States ◽  
Design System ◽  
Engine Design ◽  
Critical Feedback ◽  
Gas Turbine Nozzle

This paper presents a practical approach to designing a gas turbine nozzle with the help of the Aircraft Engine Design textbook as well as the software program Nozzle, a subprogram within the Aircraft Engine Design System Analysis Software suite AEDsys. The current textbook and software allow for a variable wetted length of the converging and diverging nozzle sections. Critical feedback from industry experts has inspired an attempt to design a nozzle with fixed wetted material lengths. This paper is written to augment classroom treatment, but will also support others who use the Aircraft Engine Design text and software for a preliminary engine design capstone. This approach is further guided by the actual scaling of the Pratt & Whitney F100 variable geometry converging-diverging nozzle, where wetted lengths are fixed. The chief goal is to equip students at the United States Air Force Academy with a refined approach that is more realistic of a manufactured nozzle design, producing a graphical representation of a nozzle schedule at different speed and altitude flight conditions, both with and without afterburner.

Practical Implications of Integrating Turbomachinery Into the Air Turborocket

2004 ◽  
Author(s):  
Joshua A. Clough ◽  
Mark J. Lewis
Keyword(s):  
Gas Turbine ◽  
Aircraft Engine ◽  
Launch Vehicle ◽  
Turbine Engines ◽  
Inlet Temperature ◽  
Gas Turbine Engines ◽  
Turbine Inlet Temperature ◽  
Turbine Engine ◽  
Space Launch ◽  
Practical Implications

The development of new reusable space launch vehicle concepts has lead to the need for more advanced engine cycles. Many two-stage vehicle concepts rely on advanced gas turbine engines that can propel the first stage of the launch vehicle from a runway up to Mach 5 or faster. One prospective engine for these vehicles is the Air Turborocket (ATR). The ATR is an innovative aircraft engine flowpath that is intended to extend the operating range of a conventional gas turbine engine. This is done by moving the turbine out of the core engine flow, alleviating the traditional limit on the turbine inlet temperature. This paper presents the analysis of an ATR engine for a reusable space launch vehicle and some of the practical problems that will be encountered in the development of this engine.

An Integrated Approach to Simulate Gas Turbine Secondary Air System

2020 ◽  
Author(s):  
Ali Izadi ◽  
Seyed Hossein Madani ◽  
Seyed Vahid Hosseini ◽  
Mahmoud Chizari
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Great Influence ◽  
Integrated Approach ◽  
Cfd Modeling ◽  
Connectivity Matrix ◽  
Analysis Tool ◽  
Air System ◽  
Secondary Air

Abstract One of the most critical parts of a modern gas turbine that its reliability and performance has a great influence on cycle efficiency is the secondary air system (SAS). Modern systems functions to supply not only cooling air flow for turbine blades and vanes but sealing flow for bearing chambers and turbine segments as well as turbine disks’ purge flow in order to eliminate hot gas ingestion. Due to the various interactions between SAS and main gas, consideration of the former is substantially crucial in design and analysis of the whole engine. Geometrical complexities and centrifugal effects of rotating blades and disks, however, make the flow field and heat transfer of the problem so complicated AND too computationally costly to be simulated utilizing full 3-D CFD methods. Therefore, developing 1-D and 0-D tools applying network methods are of great interests. The present article describes a modular SAS analysis tool that is consisted of a network of elements and nodes. Each flow branch of a whole engine SAS network is substituted with an element and then, various branches (elements) intersect with each other just at their end nodes. These elements which might include some typical components such as labyrinth seals, orifices, stationary/rotating pipes, pre-swirls, and rim-seals, are generally articulated with characteristic curves that are extracted from high fidelity CFD modeling using commercial software such as Flowmaster or ANSYS-CFX. Having these curves, an algorithm is developed to calculate flow parameters at nodes with the aid of iterative methods. The procedure is based on three main innovative ideas. The first one is related to the network construction by defining a connectivity matrix which could be applied to any arbitrary network such as hydraulic or lubrication networks. In the second one, off-design SAS calculation will be proposed by introducing some SAS elements that their characteristic non-dimensional curves are influenced by their inlet total pressure. The last novelty is the integration of the blades coolant calculation process that incorporates external heat transfer calculation, structural conduction and coolant side modeling with SAS network simulation. Finally, SAS simulation of an industrial gas turbine is presented to illustrate capabilities of the presented tool in design point and off-design conditions.

scholarly journals Advanced Technology for Reducing Aircraft Engine Pollution

1974 ◽  
Vol 96 (4) ◽  
pp. 1354-1360 ◽  
Author(s):  
R. E. Jones
Keyword(s):  
Gas Turbine ◽  
Aircraft Engine ◽  
Advanced Technology ◽  
Turbine Engines ◽  
Variable Geometry ◽  
Gas Turbine Engines ◽  
Large Reduction ◽  
Final Phase ◽  
Fuel Staging ◽  
Develop Technology

The proposed EPA regulations covering emissions of gas turbine engines will require extensive combustor development. The NASA is working to develop technology to meet these goals through a wide variety of combustor research programs conducted in-house, by contract, and by university grant. In-house efforts using the swirl-can modular combustor have demonstrated sizable reduction in NOx emission levels. Testing to reduce idle pollutants has included the modification of duplex fuel nozzles to air-assisted nozzles and an exploration of the potential improvements possible with combustors using fuel staging and variable geometry. The Experimental Clean Combustor Program, a large contracted effort, is devoted to the testing and development of combustor concepts designed to achieve a large reduction in the levels of all emissions. This effort is planned to be conducted in three phases with the final phase to be an engine demonstration of the best reduced emission concepts.

Cycle Optimization Potential of Composite Cycle and Turbocompound Aero-Engines

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Felix Klein ◽  
Stephan Staudacher
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Exchange Process ◽  
Aircraft Engine ◽  
Time Frame ◽  
Fuel Burn ◽  
Component Efficiency ◽  
Low Efficiency ◽  
Aero Engines

Abstract Fair comparison of future aircraft engine concepts requires the assumption of similar technological risk and a transparent book keeping of losses. A 1000 km and a 7000 km flight mission of a single-aisle airplane similar to the Aribus A321neo LR have been used to compare composite cycle engines, turbocompound engines and advanced gas turbines as potential options for an entry-into-service time frame of 2050+. A 2035 technology gas turbine serves as reference. The cycle optimization has been carried out with a peak pressure ratio of 250 and a maximum cycle temperature of 2200 K at cruise as boundary conditions. With the associated heat loss and the low efficiency of the gas exchange process limiting piston component efficiency, the cycle optimization filtered out composite cycle concepts. Taking mission fuel burn (MFB) as the most relevant criterion, the highest MFB reduction of 13.7% compared to the 2035 reference gas turbine is demonstrated for an air-cooled turbocompound concept with additional combustion chamber. An intercooled, hectopressure gas turbine with pressure gain combustion achieves 20.6% reduction in MFB relative to the 2035 reference gas turbine.

Probabilistic Fretting Fatigue Assessment of Aircraft Engine Disks

2009 ◽  
Author(s):  
Michael P. Enright ◽  
Kwai S. Chan ◽  
Jonathan P. Moody ◽  
Patrick J. Golden ◽  
Ramesh Chandra ◽  
...  
Keyword(s):  
Fatigue Crack ◽  
Fatigue Crack Growth ◽  
Gas Turbine ◽  
Crack Growth ◽  
Stress Gradient ◽  
Random Variables ◽  
Aircraft Engine ◽  
Fretting Fatigue ◽  
Turbine Engine ◽  
Engine Components

Fretting fatigue is a random process that continues to be a major source of damage associated with the failure of aircraft gas turbine engine components. Fretting fatigue is dominated by the fatigue crack growth phase and is strongly dependent on the magnitude of the stress values in the contact region. These stress values often have the most influence on small cracks where traditional long-crack fracture mechanics may not apply. A number of random variables can be used to model the uncertainty associated with the fatigue crack growth process. However, these variables can often be reduced to a few primary random variables related to the size and location of the initial crack, variability associated with applied stress and crack growth life models, and uncertainty in the quality and frequency of non-deterministic inspections. In this paper, an approach is presented for estimating the risk reduction associated with non-destructive inspection of aircraft engine components subjected to fretting fatigue. Contact stress values in the blade attachment region are estimated using a fine mesh finite element model coupled with a singular integral equation solver and combined with bulk stress values to obtain the total stress gradient at the edge of contact. This stress gradient is applied to the crack growth life prediction of a mode I fretting fatigue crack. A probabilistic model of the fretting process is formulated and calibrated using failure data from an existing engine fleet. The resulting calibrated model is used to quantify the influence of inspection on the probability of fracture of an actual military engine disk under real life loading conditions. The results can be applied to quantitative risk predictions of gas turbine engine components subjected to fretting fatigue.

scholarly journals Mode-specific, semi-volatile chemical composition of particulate matter emissions from a commercial gas turbine aircraft engine

2019 ◽  
Vol 218 ◽  
pp. 116974
Author(s):  
Zhenhong Yu ◽  
Michael T. Timko ◽  
Scott C. Herndon ◽  
Richard, C. Miake-Lye ◽  
Andreas J. Beyersdorf ◽  
...  
Keyword(s):  
Particulate Matter ◽  
Chemical Composition ◽  
Gas Turbine ◽  
Aircraft Engine ◽  
Particulate Matter Emissions
Sign in / Sign up

Export Citation Format

Share Document